Landing Pattern: Loiter to alt optional support

Show correct item editor based on current VTOL state

Fix unit test crash

Correct handling of terrain ready when loading back from file

Mavlink terrain protocol support

Fix MAV_CMD_IMAGE_START_CAPTURE unit test usage for take photo

FW Landing Pattern: Support for stop photo/video. Plus item unit test.

Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

Added param2 for start video capture (update interval)
Excluded param2 above from PX4 as it's fixed to 0.2Hz
Re-added param2 test within CameraSectionTest (start video capture)

Mavlink spec changed

Move set camera photo mode to be first item

Fixed all the bugs the new tests found